Senator Patty Murray, D-Wash., announced on Wednesday that she has opened an investigation into whether or not military hospitals have denied treatment to service members with post-traumatic stress disorder (PTSD), possibly as a means to cut costs.

The Army is currently conducting its own investigation — spurred by recent revelations that 40% of PTSD diagnoses at Madigan Army Medical Center in Washington state had been reversed — but Murray, chair of the Senate Veterans' Affairs Committee, said she is conducting her own investigation to ensure Army officials "don't just bury this under the rug."

"I will not be satisfied until I know that they have done an absolutely in-depth evaluation and found every soldier that may have been misdiagnosed — in a timely manner — and get them the care they need," Murray told McClatchy Newspapers.

PTSD is a common response to surviving a traumatic event, such as combat, rape, assault or natural disaster. Symptoms can include hypervigilance, nightmares, flashbacks, and avoidance of situations that may be reminders of the traumatizing experience. According to the National Institute of Mental Health, approximately 6.8% of the U.S. adult population experiences PTSD during their lifetimes, and less than half of those people receive even "minimally adequate" treatment. The number of PTSD cases for combat veterans is much higher. According to the National Center for PTSD, a division of the Department of Veterans Affairs, between 11-20% of veterans from the Iraq and Afghanistan wars suffer from PTSD.

Veterans diagnosed with PTSD are entitled to additional health and financial benefits.

Murray announced her investigation Wednesday while questioning Army Surgeon General Lieutenant General Patricia Horoho regarding the Madigan case, asking if the same diagnosis reversal might be happening on other bases.

The senator has been looking into the Madigan case since it first came to light in January. Last week, she told the Seattle Times that of the 1,680 patients screened at Madigan since 2007, 690 had been diagnosed with PTSD, but more than 290 of those diagnoses were later reversed. According to a memo from an Army Medical Command ombudsman obtained by the Times, a soldier's PTSD diagnosis can cost taxpayers up to $1.5 million over his or her lifetime.

Army Secretary John McHugh told a Senate hearing last week that the Army has instituted a system-wide review of PTSD diagnostic processes, calling attempts to consider the financial implications of a diagnosis "simply unacceptable."

Senator Murray's questioning of Army Surgeon General Lieutenant General Patricia Horoho appears below: